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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - arch/arm/mm/flush.c
2 * linux/arch/arm/mm/flush.c
4 * Copyright (C) 1995-2002 Russell King
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 #include <linux/module.h>
12 #include <linux/pagemap.h>
14 #include <asm/cacheflush.h>
15 #include <asm/system.h>
17 static void __flush_dcache_page(struct address_space
*mapping
, struct page
*page
)
19 struct mm_struct
*mm
= current
->active_mm
;
20 struct vm_area_struct
*mpnt
;
21 struct prio_tree_iter iter
;
25 * Writeback any data associated with the kernel mapping of this
26 * page. This ensures that data in the physical page is mutually
27 * coherent with the kernels mapping.
29 __cpuc_flush_dcache_page(page_address(page
));
32 * If there's no mapping pointer here, then this page isn't
33 * visible to userspace yet, so there are no cache lines
34 * associated with any other aliases.
40 * There are possible user space mappings of this page:
41 * - VIVT cache: we need to also write back and invalidate all user
42 * data in the current VM view associated with this page.
43 * - aliasing VIPT: we only need to find one mapping of this page.
45 pgoff
= page
->index
<< (PAGE_CACHE_SHIFT
- PAGE_SHIFT
);
47 flush_dcache_mmap_lock(mapping
);
48 vma_prio_tree_foreach(mpnt
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
) {
52 * If this VMA is not in our MM, we can ignore it.
54 if (mpnt
->vm_mm
!= mm
)
56 if (!(mpnt
->vm_flags
& VM_MAYSHARE
))
58 offset
= (pgoff
- mpnt
->vm_pgoff
) << PAGE_SHIFT
;
59 flush_cache_page(mpnt
, mpnt
->vm_start
+ offset
, page_to_pfn(page
));
63 flush_dcache_mmap_unlock(mapping
);
67 * Ensure cache coherency between kernel mapping and userspace mapping
70 * We have three cases to consider:
71 * - VIPT non-aliasing cache: fully coherent so nothing required.
72 * - VIVT: fully aliasing, so we need to handle every alias in our
74 * - VIPT aliasing: need to handle one alias in our current VM view.
76 * If we need to handle aliasing:
77 * If the page only exists in the page cache and there are no user
78 * space mappings, we can be lazy and remember that we may have dirty
79 * kernel cache lines for later. Otherwise, we assume we have
82 void flush_dcache_page(struct page
*page
)
84 struct address_space
*mapping
= page_mapping(page
);
86 if (cache_is_vipt_nonaliasing())
89 if (mapping
&& !mapping_mapped(mapping
))
90 set_bit(PG_dcache_dirty
, &page
->flags
);
92 __flush_dcache_page(mapping
, page
);
94 EXPORT_SYMBOL(flush_dcache_page
);